Three space travellers, including South Korea's first astronaut, returned to Earth on Saturday aboard a Russian space capsule that landed about 420 kilometres off target in northern Kazakhstan.

The Soyuz craft likely missed its planned landing point because it followed a "ballistic" or very steep trajectory upon re-entry, said NASA commentator John Ira Petty, monitoring the descent from the Johnson Space Center in Houston, Tex.

Ground crew members help U.S. astronaut Peggy Whitson after a re-entry that subjected her and two other space travellers to severe G-forces.Ground crew members help U.S. astronaut Peggy Whitson after a re-entry that subjected her and two other space travellers to severe G-forces.
(Shamil Zhumatov/Associated Press)

Besides being far off course, the landing, on a return from the International Space Station, was about 20 minutes later than planned.

South Korean bioengineer Yi So-yeon, American astronaut Peggy Whitson and Russian flight engineer Yuri Malenchenko were reported to be in satisfactory condition, Russian mission control spokesman Valery Lyndin said.

Once a recovery helicopter arrived, the crew were examined by medical officials.

Yi, a nanotechnology engineer from Seoul, travelled to the space station on April 10 along with cosmonauts Sergei Volkov and Oleg Kononenko, who have replaced Whitson and Malenchenko.